Distance between two points: why do I keep plugging values in wrong spots?

  • Context:
  • Thread starter Thread starter OMGMathPLS
  • Start date Start date
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
3 replies · 1K views
OMGMathPLS
Messages
64
Reaction score
0
Find exact distance between two points. (2, -2) (5, 2)

I plug in the distance formula but I get

sq rt (5-2)^2+ (2-(1)^2

and I get 9 on both sides so that's sq rt 18 = 4.24

but the book says it's 5

so i don't know what I'm doing wrong. Help please.

- - - Updated - - -

Wait, I see i plugged it in the wrong spot. Oh thank God it was that simple. Oh thank you Jesus.

- - - Updated - - -

Ok, so my new question is is it normal to have a hard time plugging into the spots. I feel dyslexic as I am doing this. is there a trick to remember it?
 
Mathematics news on Phys.org
You want to use:

$$d=\sqrt{(5-2)^2+(2-(-2))^2}=\sqrt{3^2+4^2}=\sqrt{25}=5$$

You see, the distance formula states that given two points $\left(x_1,y_1\right)$ and $\left(x_2,y_2\right)$. then the distance $d$ between these points is given by:

$$d=\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$$
 
MarkFL said:
You want to use:

$$d=\sqrt{(5-2)^2+(2-(-2))^2}=\sqrt{3^2+4^2}=\sqrt{25}=5$$

You see, the distance formula states that given two points $\left(x_1,y_1\right)$ and $\left(x_2,y_2\right)$. then the distance $d$ between these points is given by:

$$d=\sqrt{\left(x_2-x_1\right)^2+\left(y_2-y_1\right)^2}$$

Thanks MarkFl

I want to ask you, how do you keep from getting the variables confused amongst each other and how many times do you recheck to make sure it's correct? How old were you when you first learned this level of math?
 
OMGMathPLS said:
Ok, so my new question is is it normal to have a hard time plugging into the spots. I feel dyslexic as I am doing this. is there a trick to remember it?

It just takes practice...you are not alone in finding it a challenge at times to know which of the given data values goes into which place in a formula. :D

I have had lots and lots of practice over the last 23 years. I was 27 when I really began studying mathematics.

Just make certain you understand what each parameter in a given formula represents. ;)